Missing Elements in Array

Appproach 1 : Using HashMap. Store wat's there in given array. Key would be value of the array and value will also be the same.
Time complexity : O(N)
Space Complexity : O(N). Result array has been created to add the missing elements
class Solution:
    def findDisappearedNumbers(self, nums: List[int]) -> List[int]:
        hashmap={}
        print(len(nums))
        for num in nums:
            hashmap[num]=num ### Store all the values of the array as the key value pairs 
        print(hashmap)
        result=[] ### to store the missing values
        for num in range(1,len(nums)+1):
            if num not in hashmap:
                result.append(num)
        return result
        
  Approach2 : Inplace solution. Make use of input array to mark the numbers visited and then find our missing numbers.
  Treat the numbers in the array as indices and mark the corresponding locations as negative
  class Solution:
    def findDisappearedNumbers(self, nums: List[int]) -> List[int]:
        result=[]
        for i in range(len(nums)):
            temp=nums[i]
            ## if found index element is negative 
            if temp<0:
                temp*=-1 ### Absolute value
                #temp=abs(temp)-1
            if nums[temp-1]>0:
                nums[temp-1]*=-1
        for i in range(len(nums)):
            if nums[i]>0:
                result.append(i+1)
        return result